Partial Dentures are made from chrome-cobalt metal, the very
same metal used for screws, plates, etc. that are implanted into
the body either temporarily, or permanently. This metal requires
a very high heat investment that is not required to reproduce
extra-fine detail like crown and bridge investment. It is stable
and does reproduce your original pretty closely. This
metal/proceedure is best left to specialists. If you need
something done in this metal, take your wax-up to a dental lab
that specializes in chrome casting and ask them to do it. I’m
sure they will do it for you for a nominal fee. The tech will
probably ride it along with another casting if it isn’t very big.
Be prepared to grind your ass off, and burn your fingers a lot.
This crap is harder than Janet Renos testicles! The techs that
finish this metal keep a bowl of water handy, otherwise they
would be there all day working on one object. If the Egyptians
of antiquity had this metal, the objects would look like they
were made yesterday even after being buried for 4000 years.
Now to nickel chrome. This metal requires a high heat dental
alloy investment capable of a 1500-1700 degree F. burnout. Its
specific gravity is fairly light compared to precious metals, so
it requires an extra wind on the centrifugal casting machine and
the attendant re-balancing of the broken-arm. The metal is cheep
enough though and you should be able to find it at any dental
supply house. There are many brands out there, but for your use
you needn’t worry about which brand to buy. Ask the supply house
for a tech sheet and follow their instructions to the letter.
If you are going to solder this to anything, as always you must
be clean, but also, once you put the flame on it you don’t ever
take it off until you are complete, or the metal will oxidize in
a flash and you will need to start from scratch on the soldering.
Before you reuse the button for a new casting you must sand
blast or grind it clean of all oxides. If you don’t add at least
50% new metal to the next casting you will get pitting that will
make anything you have ever gotten in precious metal seem
inconsequential by comparison.
When you finish this metal, don’t even try steel burrs, you need
carbide(good quality) and aluminous oxide stones. Rubber it
with a harder grit rubber wheel or point and work your way to
softer grit. You can then use a mounted brush with a carborundum
based compound(tripoli may work) then red rouge. It will take a
It is hard to cast, hard to finish, and about 18% of the people
are nickel sensitive to a greater or lesser degree. I first used
this metal 20 yrs. ago when I managed a friends lab and started
noticing that I got nose bleeds, and the unavoidable cuts, nicks,
and scrapes would not heal plus the area under my wedding ring
was raw, so before I went on a 2 week vacation I cast a thin
10x10mm square of this metal. At the beginning of the second
week of the fishing trip, I put it on the pad of a band-aid and
kept it taped to the inside of my upper arm. Within 4 days I had
a red raw welt. I will not have this metal in my mouth or in my
If I can help in any way, E-mail me directly.
NRA Endowment and